When printing paper sheets on a printing machine at a prescribed position on the paper sheets under the same conditions, it is necessary that the corners of the paper sheets be aligned. For cutting paper sheets of different sizes to the same dimentions, it is necessary to align at least two edges of the paper sheets. Heretofore, since such a paper jogging process has entirely been effected manually, the process has been quite laborious and time-consuming, and it has been rather difficult to align paper sheets uniformly.